Filter System with Integral Media Retainer Seal

ABSTRACT

A filter system having a filter media retainer seal includes: at least one underdrain block having a top wall, a bottom wall, and a pair of side walls extending between the top wall and the bottom wall; a filter media retainer mounted onto the top wall of the at least one underdrain block; and at least one rib positioned between the underdrain block and the filter media retainer. The at least one rib forms a seal between the underdrain block and the filter media retainer, and prevents filter media from entering the underdrain block. The at least one rib can be monolithically formed to the at least one underdrain block. Alternatively, the at least one rib is monolithically formed to the filter media retainer. The rib is crushable and/or it bites into a surface on the adjoining part to reduce or eliminate the need for a separate sealant.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.14/026,526, filed Sep. 13, 2013, which claims the benefit of UnitedStates Provisional Application No. 61/701,254, filed Sep. 14, 2012, bothof which are hereby incorporated in their entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates generally to a filter system forfiltering a liquid containing particles, and, in particular, to a filtersystem that includes an integral media retainer seal.

2. Description of Related Art

Gravity filters are used to separate water from suspended solids. Themain components of gravity filters are filtering media and underdrainblocks. Underdrain blocks are generally square or rectangular in crosssection and have a long longitudinal axis as compared to their crosssection. They are attached end-to-end to form long sections calledlaterals. When using a mono-pour installation method, underdrainlaterals are attached to the filter floor using a series of anchor rods,horizontal supports, and grouting.

The filtering media is used to capture dirt particles from a liquidbeing filtered as the liquid passes through the media. The filter mediais supported by a filter media retainer so that it will not pass intothe underdrain block or collection system. The filter media retainer isoften a plate or plurality of plates that are placed on top of theunderdrain block. To further prevent filter media from passing into theunderdrain block, a sealant is inserted between the filter mediaretainer and underdrain block.

Typically, the sealant inserted between the filter media retainer andunderdrain block is caulk, high tack synthetic rubber tape, and thelike. However, these sealants have several drawbacks. For instance,these sealants are expensive, and it is time-consuming to apply themduring assembly of the filter system. In addition, an incomplete sealingarrangement around the top of the underdrain block can allow filtermedia to pass into the underdrain block after multiple uses.

In view of the foregoing, a need exists for a filter system thatincludes an integrated structural component that is capable of forming aseal between the filter media retainer and underdrain block.

SUMMARY OF THE INVENTION

In one non-limiting embodiment, the present invention relates to anunderdrain block for a filter system. The underdrain block includes atop wall, a bottom wall, a pair of side walls extending between the topwall and the bottom wall, and at least one crushable rib that ismonolithically formed to the top wall of the underdrain block. The ribprojects out from the top wall of the underdrain block at a heightranging from 0.01 inches to 0.05 inches, and has a width ranging from0.01 inches to 0.05 inches. The rib can also be formed into a variety ofshapes including a triangular shape.

The underdrain block can have only one rib or it can have a plurality ofribs projecting out from the top wall. When the underdrain blockincludes a plurality of ribs, the plurality of ribs can project out fromthe top wall at different heights ranging from 0.01 inches to 0.05inches. The rib or ribs can include an intermittent rib, a continuousrib, combinations of intermittent ribs, combinations of continuous ribs,or combinations of intermittent and continuous ribs in a pattern eithersingle or in parallel or a series of parallel configurations. In oneembodiment, the rib or ribs can extend continuously around a perimeterof the top wall of the underdrain block. Further, the underdrain block,including the crushable rib monolithically formed thereto, can be madeof a variety of materials such as high density polyethylene.

The underdrain block can also have a rail that extends along at leastone side of the top wall of the underdrain block. The rail can projectout of the top wall of the underdrain block in a direction opposite thebottom wall. In one embodiment, the rail is positioned outside thecrushable rib and extends along at least one outer side edge of the topwall of the underdrain block. In this embodiment, the rail can act as aprotective barrier for the crushable rib.

In another non-limiting embodiment, the crushable rib is formed directlyto an inside wall of the rail instead of the top wall of the underdrainblock. The rib can be monolithically formed to the rail. The ribprojects out from the inside wall of the rail in the same manner the ribcan project out from the top wall of the underdrain block describedabove.

The present invention also relates to a filter media retainer. Thefilter media retainer includes a top surface, a bottom surface, and atleast one rib projecting out from the bottom surface. The at least onerib can be monolithically formed to the bottom surface of the filtermedia retainer. The at least one rib can project out from the bottomsurface of the filter media retainer at a height ranging from 0.01inches to 0.05 inches.

In one embodiment according to the present invention, the filter mediaretainer includes a plurality of ribs projecting out from the bottomsurface. The plurality of ribs projecting out from the bottom surfacecan have different heights ranging from 0.01 inches to 0.05 inches. Therib or ribs can include an intermittent rib, a continuous rib,combinations of intermittent ribs, combinations of continuous ribs, orcombinations of intermittent and continuous ribs in a pattern eithersingle or in parallel or a series of parallel configurations. In anon-limiting embodiment, the at least one rib extends continuouslyaround a perimeter of the bottom surface of the filter media retainer.The filter media retainer can be made of a high strength plasticincluding, but not limited to, acrylonitrile butadiene styrene (ABS),glass filled ABS, and blends of polyphenylene oxide and polystyrene.

The present invention also relates to a filter system that includes afilter media retainer seal. The filter system can include: at least oneunderdrain block having a top wall, a bottom wall, and a pair of sidewalls extending between the top wall and the bottom wall; a filter mediaretainer mounted onto the top wall of the at least one underdrain block;and at least one rib positioned between the underdrain block and thefilter media retainer. The at least one rib forms a seal between theunderdrain block and the filter media retainer, and prevents filtermedia from passing into the underdrain block. The at least one rib canbe monolithically formed to the underdrain block. When the filter mediaretainer is mounted onto the underdrain block, the at least one ribcollapses. In another embodiment, the at least one rib is monolithicallyformed to the filter media retainer, and when the filter media retaineris mounted to the underdrain block, the at least one rib bites into theunderdrain block.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an underdrain block and a filter mediaretainer in accordance with the present invention;

FIG. 2 is a cross-sectional view of the underdrain block and filtermedia retainer of FIG. 1;

FIG. 3 is a detailed perspective view of an underdrain block showing arib in accordance with a first embodiment of the present invention;

FIG. 4A is a detailed perspective view of the underdrain block of FIG.3;

FIG. 4B is a detailed perspective view of an underdrain block with a ribin accordance with a second embodiment of the present invention;

FIG. 5 is a perspective view of the underdrain block of FIG. 3;

FIG. 6 is a detailed bottom view of a filter media retainer inaccordance with a third embodiment of the present invention; and

FIG. 7 is a perspective view of an assembled underdrain block and filtermedia retainer in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of the description hereinafter, the terms “upper,” “lower,”“right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” “lateral,”“longitudinal,” and derivatives thereof shall relate to the invention asit is oriented in the drawing figures. However, it is to be understoodthat the invention may assume alternative variations and step sequences,except where expressly specified to the contrary. It is also to beunderstood that the specific devices and processes illustrated in theattached drawings, and described in the following specification, aresimply exemplary embodiments of the invention. Hence, specificdimensions and other physical characteristics related to the embodimentsdisclosed herein are not to be considered as limiting.

Referring to FIG. 1, a gravity or pressure filter system 10 inaccordance with the present invention includes at least one underdrainblock 12 and a filter media retainer 14 which is mounted on top of theunderdrain block 12. A layer or multiple layers of filter media (notshown) is poured on top of the filter media retainer 14. As describedabove, the filter media acts to remove undesirable particles from aliquid that is being filtered through the filter system 10.

As shown in FIG. 2, the underdrain block 12 has a plurality of exteriorwalls including a top wall 18, a bottom wall 20, and a pair of sidewalls 22 extending between the top wall 18 and the bottom wall 20. Aplurality of internal walls 24 divide the hollow interior of theunderdrain block 12 into a primary horizontal conduit 26 and twosecondary horizontal conduits 28 positioned on opposite sides of primaryhorizontal conduit 26. Additionally, a plurality of channels 32 areprovided on internal walls 24 to provide fluid communication betweenprimary horizontal conduit 26 and secondary horizontal conduits 28.

The underdrain block 12 can be made from structural foam including, butnot limited to, high density polyethylene (HDPE). HDPE providesstructural strength as well as corrosion resistance. Other structuralfoams that can be used include, but are not limited to, low densitypolyethylene (LDPE) and polyvinyl chloride (PVC).

In accordance with one embodiment of the present invention, and as shownin FIGS. 3-5, the underdrain block 12 can include a rib 34. The rib 34can be monolithically formed to the top wall 18 of the underdrain block12, as shown in FIGS. 3, 4A, and 5. As used herein, “monolithicallyformed” refers to components or structures that are formed or cast as asingle piece. Accordingly, a rib 34 that is monolithically formed intothe top wall 18 of an underdrain block 12 refers to an underdrain block12 that is cast with a rib 34 projecting from the top wall 18 of theunderdrain block 12. For instance, in one embodiment, a rib 34 ismonolithically formed on the top wall 18 of an underdrain block 12during the manufacturing of the underdrain block 12.

The rib 34 formed on the top wall 18 of the underdrain block 12 canproject out from the top wall 18 from about 0.01 inches to about 0.05inches. Similarly, the width of the rib 34 can range from about 0.01inches to about 0.05 inches. In addition, the rib 34 can be formed intoa variety of shapes. For instance, and as shown in FIG. 4A, the rib 34can have a triangular shape.

In a non-limiting embodiment, the underdrain block 12 includes aplurality of ribs 34 projecting out of the top wall 18. The plurality ofribs 34 can extend around a portion of the perimeter of the top wall 18of the underdrain block 12, or the plurality of ribs 34 can extendaround the entire outer perimeter of the top wall 18 of the underdrainblock 12. The plurality of ribs 34 can be aligned in a consecutive row.The plurality of ribs 34 can be a combination of intermittent ribs 34and can be spaced apart. Alternatively, the consecutively alignedplurality of ribs 34 can be positioned such that each rib 34 abuts thenext consecutive rib 34. In this embodiment, the consecutively alignedplurality of ribs 34 can form a substantially continuous barrier. Insome embodiments, the plurality of ribs 34 includes combinations ofcontinuously aligned ribs 34. Further, in certain embodiments, theplurality of ribs 34 includes a combination of intermittent andcontinuous sets of ribs 34. The plurality of ribs 34 can be formed in apattern such as a single or in parallel or series of parallelconfigurations. The plurality of ribs 34 can project out from the topwall 18 at the same height or at different heights ranging from 0.01inches to 0.05 inches.

In another embodiment, the underdrain block 12 includes one rib 34 witha length that extends around a portion of the perimeter of the top wall18. As shown in FIG. 5, the underdrain block 12 can also include a rib34 with a length that extends around the entire perimeter of the topwall 18, thereby forming a continuous wall around the perimeter of thetop wall 18.

The rib 34 can be made of the same material as the underdrain block 12.For instance, both the underdrain block 12 and the rib 34 can be made ofHDPE. Typically, when the rib 34 is monolithically formed on the topwall 18 of the underdrain block 12, the rib 34 and the underdrain block12 are made of the same material. In another non-limiting embodiment,the underdrain block 12 and rib 34 are made of different materials.

Referring to FIGS. 3-5, the underdrain block 12 can also include a rail40 that projects substantially out from the top wall 18 in a directionopposite the bottom wall 20. The rail 40 can be monolithically formedwith the underdrain block 12. The height of the rail 40 projecting outfrom the top wall 18 ranges from 0.15 inches to about 0.50 inches. Thelength of the rail 40 extends along a portion of at least one side ofthe top wall 18. In one embodiment, the rail 40 is positioned outsidethe rib 34 and extends along at least one outer side edge of the topwall 18 of the underdrain block 12 that is adjacent and connected to aside wall 22 of the underdrain block 12. This forms a barrier along atleast one outer side edge of the top wall 18. In a non-limitingembodiment shown in FIG. 5, the underdrain block 12 includes two rails40 that extend along the entire outer side edges of the top wall 18. Thetwo rails 40 provide a protective barrier for the rib 34 formed on thetop wall 18. This prevents objects from damaging the rib 34 prior toassembling the filter system 10.

In a non-limiting embodiment, as shown in FIG. 4B, the rib 34 is formeddirectly to an inside wall 42 of the rail 40 instead of the top wall 18of the underdrain block 12. The rib 34 can be monolithically formed tothe rail 40. The rib 34 projects out from the inside wall 42 of the rail40 in the same manner the rib 34 projects out from the top wall 18 ofthe underdrain block 12 described above. Accordingly, the rib 34 formedto the inside wall 42 of the rail 40 can project out from the rail 40about 0.01 inches to about 0.05 inches. Similarly, the width of the rib34 can range from about 0.01 inches to about 0.05 inches. In addition,the rib 34 can be formed into a variety of shapes.

After the rib 34 and underdrain block 12 are formed, a filter mediaretainer 14 can be mounted onto the top wall 18 of the underdrain block12. The filter media retainer 14 can be made of a high strength plasticincluding, but not limited to, ABS, glass filled ABS, and blends ofpolyphenylene oxide and polystyrene such as the plastic product soldcommercially by the Saudi Basic Industries Corporation under thetradename NORYL®. The filter media retainer 14 is shaped and configuredto fixedly engage with the underdrain block 12 when mounted onto theunderdrain block 12. In one embodiment, the filter media retainer 14 isfastened to the top of the underdrain block 12. For instance, theunderdrain block 12 can include mounting holes positioned on the topwall 18 and the filter media retainer 14 can include fasteners that areadapted to attach to the mounting holes. In one embodiment, the filtermedia retainer 14 is fastened into the top of the underdrain block 12with fasteners including, but not limited to, screws.

As shown in FIG. 1, the filter media retainer 14 can include a filtermedia retainer plate or a plurality of connected plates that areinterconnected to form the filter media retainer 14. Such a filter mediaretainer 14 is described in U.S. patent application Ser. No. 13/553,897,the entire disclosure of which is hereby expressly incorporated hereinby reference.

When mounted onto the underdrain block 12, the filter media retainer 14engages the rib 34 projecting from the top wall 18 of the underdrainblock 12. Alternatively, in another embodiment, the filter mediaretainer 14 engages the rib 34 projecting out from an inside wall 42 ofthe rail 40. The engagement between the filter media retainer 14 and therib 34 creates a seal between the underdrain block 12 and the filtermedia retainer 14, which prevents filter media from entering theunderdrain block 12.

In a non-limiting embodiment, the filter media retainer 14 is made of aharder material than the rib 34. For instance, the rib 34 can be made ofHDPE and the filter media retainer 14 can be made of ABS. When a filtermedia retainer 14 made of ABS or a similar material is mounted andfastened onto an underdrain block 12 that includes a rib 34 made ofHDPE, the rib 34 will collapse or crush from the force applied by thefilter media retainer 14. The crushed rib 34 creates the seal betweenthe filter media retainer 14 and the underdrain block 12.

In accordance with another embodiment of the present invention, as shownin FIG. 6, the underdrain block 12 does not include a rib 34. Rather,the filter media retainer 14 includes a rib 50 that projects out fromthe bottom surface 15 of the filter media retainer 14. The rib 50 can bemonolithically formed on the bottom surface 15 of the filter mediaretainer 14. For instance, in one embodiment, a rib 50 is monolithicallyformed on the bottom surface 15 of the filter media retainer 14 duringthe manufacturing of the filter media retainer 14.

Similar to the rib 34 of the underdrain block 12, the rib 50 of thefilter media retainer 14 can project out from the bottom surface 15about 0.01 inches to about 0.05 inches and can have a width that rangesfrom about 0.01 inches to about 0.05 inches. The rib 50 can also bemolded into a variety of shapes including, but not limited to, atriangular shape.

In one embodiment, the rib 50 can be made of the same material as thefilter media retainer 14. For instance, both the filter media retainer14 and the rib 50 can be made of ABS. Typically, when the rib 50 ismonolithically formed on the bottom surface 15 of the filter mediaretainer 14, the rib 50 and the filter media retainer 14 are made of thesame material. In another non-limiting embodiment, the filter mediaretainer 14 and rib 50 are made of different materials.

The filter media retainer 14 can include a plurality of ribs 50projecting out of the bottom surface 15. The plurality of ribs 50 canextend around a portion of the perimeter of the bottom surface 15 of thefilter media retainer 14, or the plurality of ribs 50 can extend aroundthe entire perimeter of the bottom surface 15 of the filter mediaretainer 14. The plurality of ribs 50 can be aligned in a consecutiverow. The plurality of ribs 50 can also be a combination of intermittentribs 50 and can be spaced apart. Alternatively, the consecutivelyaligned plurality of ribs 50 can be positioned such that each rib 50abuts the next consecutive rib 50. In this embodiment, the consecutivelyaligned plurality of ribs 50 can form a substantially continuousbarrier. In some embodiments, the plurality of ribs 50 includescombinations of continuously aligned ribs 50. Further, in certainembodiments, the plurality of ribs 50 includes a combination ofintermittent and continuous sets of ribs 50. The plurality of ribs 50can be formed in a pattern such as single or in parallel or series ofparallel configurations. The plurality of ribs 50 can project out fromthe bottom surface 15 at the same height or at different heights rangingfrom 0.01 inches to 0.05 inches.

In another embodiment, the filter media retainer 14 includes one rib 50with a length that extends around a portion of the perimeter of thebottom surface 15 of the filter media retainer 14. The filter mediaretainer 14 can also include a rib 50 with a length that extends aroundthe entire perimeter of the bottom surface 15, thereby forming a barrieraround the perimeter of the bottom surface 15.

When a filter media retainer 14 having a rib 50 is mounted and fastenedonto an underdrain block 12, the rib 50 from the filter media retainer14 bites into the top wall 18 of the underdrain block 12. For example,the rib 50 from the filter media retainer 14 can be made of a hardermaterial than the underdrain block 12 so that the rib 50 bites into thetop wall 18 of the underdrain block 12. This biting force from the rib50 creates a seal between the underdrain block 12 and the filter mediaretainer 14. The seal formed between the underdrain block 12 and thefilter media retainer 14 prevents filter media from entering theunderdrain block 12. In another embodiment, the rib 50 from the filtermedia retainer 14 is made of a different material and will collapse orcrush when the filter media retainer 14 is mounted onto an underdrainblock 12, thereby creating a seal between the underdrain block 12 andthe filter media retainer 14.

As described in detail above, the present invention includes a filtersystem 10 having at least one underdrain block 12, at least one filtermedia retainer 14 that is mounted onto the underdrain block 12, and asealing rib 34, 50 positioned between the filter media retainer 14 andthe underdrain block 12. During assembly, the filter media retainer 14is mounted onto the top wall 18 of the underdrain block 12. The filtermedia retainer 14 can then be fastened to the underdrain block 12. Forinstance, the underdrain block 12 can include mounting holes positionedon the top wall 18 and the filter media retainer 14 can includefasteners that are adapted to attach to the mounting holes. Differentfastening assemblies and configurations that are suitable for use withthe present invention are described in U.S. patent application Ser. No.13/553,897.

As detailed above, the rib 34, 50 can be monolithically formed as partof the underdrain bock 12 or as part of the filter media retainer 14.The rib 34, 50 forms a sealing engagement between the underdrain block12 and the filter media retainer 14. For example, in certainembodiments, the rib 34, 50 will collapse or crush when the filter mediaretainer 14 is mounted onto the underdrain block 12 creating a sealbetween the underdrain block 12 and the filter media retainer 14.Alternatively, in certain embodiments, the rib 34, 50 will bite into theunderdrain block 12 or filter media retainer 14 when the filter mediaretainer 14 is mounted onto the underdrain block 12 creating a sealbetween the underdrain block 12 and the filter media retainer 14. Afterthe filter media retainer 14 is sealably engaged to the underdrain block12, filter media is placed into the filter media retainer 14. FIG. 7illustrates an assembled filter system 10 with the filter media retainer14 mounted to the underdrain block 12 as described herein.

During filtration, water to be filtered comes downward through granularmedia and passes through dispersion apertures. From there, water passesto secondary horizontal conduits 28 and then to primary horizontalconduit 26. Primary horizontal conduit 26 is connected to a collectionflume (not shown), which in turn conveys the filtered liquid to aclearwell (not shown) for distribution to the consumer.

To ensure maximum filter performance, the filter media retainer 14 mustbe washed regularly. This is accomplished by pumping clean water backthrough underdrain block 12 and upward through the granular media todislodge foreign particles from the granular media. Oftentimes, toprepare the granular media for water backwash, the submerged granularmedia is first scoured with an air-only backwash, wherein air is pumpedupward through underdrain block 12. The air-only backwash loosens thedirt and other impurities so that they will be more easily carried offby the subsequent water backwash phase.

During the filtering and backwash processes, the seal created by the rib34, 50 prevents filter media from passing into the underdrain block 12.Because the rib 34, 50 is already formed to the filter media retainer 14or the underdrain block 12, the sealing process is easy, efficient, andeffortless. The need to apply a sealant is reduced or eliminatedaltogether.

While various embodiments were provided in the foregoing description,those skilled in the art may make modifications and alterations to theseembodiments without departing from the scope and spirit of theinvention. For example, it is to be understood that this disclosurecontemplates that, to the extent possible, one or more features of anyembodiment can be combined with one or more features of any otherembodiment. Accordingly, the foregoing description is intended to beillustrative rather than restrictive. The invention describedhereinabove is defined by the appended claims and all changes to theinvention that fall within the meaning and the range of equivalency ofthe claims are to be embraced within their scope.

The invention claimed is:
 1. An underdrain block for a filter system, the underdrain block comprising: a top wall, a bottom wall, a pair of side walls extending between the top wall and the bottom wall, and at least one crushable rib projecting out from the underdrain block, wherein the at least one crushable rib is monolithically formed to the underdrain block.
 2. The underdrain block of claim 1, wherein the at least one crushable rib projects out from the top wall of the underdrain block.
 3. The underdrain block of claim 2, wherein the at least one crushable rib projects out from the top wall of the underdrain block at a height ranging from 0.01 inches to 0.05 inches.
 4. The underdrain block of claim 2, wherein the at least one crushable rib comprises a width ranging from 0.01 inches to 0.05 inches.
 5. The underdrain block of claim 2, wherein the underdrain block comprises a plurality of crushable ribs projecting out from the top wall.
 6. The underdrain block of claim 5, wherein the plurality of crushable ribs projecting out from the top wall have different heights ranging from 0.01 inches to 0.05 inches.
 7. The underdrain block of claim 2, wherein the at least one crushable rib extends continuously around a perimeter of the top wall of the underdrain block.
 8. The underdrain block of claim 1, wherein the underdrain block further comprises a rail that extends along at least one outer side edge of the top wall of the underdrain block, wherein the rail projects out of the top wall of the underdrain block in a direction opposite the bottom wall.
 9. The underdrain block of claim 8, wherein the rail is monolithically formed to the underdrain block.
 10. The underdrain block of claim 9, wherein the at least one crushable rib is monolithically formed to the rail. 